Question spinning problems with Noctua NF-A12x25 PWM

Apr 11, 2021
Hi everyone, about 2 years ago i built my first pc and immediately replaced my fans with 3 Noctua NF-A12x25 PWM and, surprised by they're perfomance, i bought another 2 cause my dumb ass thought that i could just replace the fans of the cpu cooler not checking compatibility so i put them back in the box and have them as spare. about a year after the exhaust and 1 intake started to malfunction, they wouldn't spin after booting so i had to shut down and reboot my pc in order for them to spin until a month ago where i replaced them with the 2 spare i had cause i also replaced psu and case. now everything works fine, until about 3 days ago where the last not replaced yet intake started to malfunction too by not spinning at booting but spin fine after shutting down and rebooting but i feel im slowly damaging the other fans by doing this process just to make it spin (idk what to think now); after this everything works fine tho, 27°-30° degrees idle, no overheating during games and fans are responsive when changing speed and mode in aorus system information viewer but what are the odds of buying 3 faulty or to be broken in short time noctua fans? especially after hearing only good reviews and experiences by the majority of users.

gigabyte aorus ultra gaming pro
rtx 2070
core i9-7960x
corsair rm750w


SkyNetRising is right, I would bet. And this also means probably NONE of those fans are faulty. They just have slight wear so they take a slightly higher start-up setting.

BEFORE proceeding, check this item. Noctua often ships their fans with little devices they call Low Noise Adapters or LNA's. These a little bits you can insert into the fan wiring where you plug the fan into the header. All they really are is resistors that make the fan run SLOWER than the header tries to achieve. That makes less noise, BUT reduces cooling. These are NOT to be used when you are using your fan on mobo headers that already DO fan speed control for you. So IF those are inserted at the header, remove them!

For specifics how to change, see your mobo manual on p. 55. Note that you need to adjust EACH fan header that you nave case fans attached to, especially those with "problems". At top centre in the red box you choose one fan header at a time and adjust it as follows.
  1. Fan Speed Control Normal - not Silent or Manual
  2. Fan Control Use Temp Input to System1 for case fans on the SYS_FAN headers.
  3. Fan Control Mode to PWM - these Noctuas are that type
  4. Fan Stop DISabled
  5. Look at the graph of fan PWM% vs. Temp. You have five setpoints you can adjust by sliding them with your mouse. You should plan to increase the PWM% setting for the two lowest ones. Look at the upper right where it shows you the current speed of the fan. Your Nocutas have a spec of min 450 RPM. So set the lowest speed button #1 to give you a bit more - say, 500 RPM - at the lowest temp - say, about 20C. Set the second button for the next temp up to a bit higher.
  6. Go on to the next SYS_FAN header. When you have them all adjusted, use Esc to get back to Main Menu, then the F10 key to pop up an Exit menu and choose to Save Changes and Exit.
If this solves your problem, good. If it persists, go back in and set slightly higher minimum speeds for all SYS_FAN headers.